This invention generally relates to endoscopic instruments. More particularly, the present invention provides a jaw assembly for use in an endoscopic instrument.
Laparoscopic, endoscopic, and other minimally invasive surgical techniques enable surgeons to perform fairly complicated procedures through relatively small entry points in the body. The term xe2x80x9claparoscopicxe2x80x9d refers to surgical procedures performed on the interior of the abdomen, while the term xe2x80x9cendoscopicxe2x80x9d refers more generally to procedures performed in any portion of the body. Endoscopic surgery involves the use of an endoscope, which is an instrument permitting the visual inspection and magnification of a body cavity. The endoscope is inserted into a body cavity through a cannula extending through a hole in the soft tissue protecting the body cavity. The hole is made with a trocar, which includes a cutting instrument slidably and removably disposed within a trocar cannula. After forming the hole, the cutting instrument can be withdrawn from the trocar cannula. A surgeon can then perform diagnostic and/or therapeutic procedures at the surgical site with the aid of specialized medical instruments adapted to fit through the trocar cannula and additional trocar cannulas providing openings into the desired body cavity.
Some known advantages of minimally invasive surgical techniques include reduced trauma to the patient, reduced likelihood of infection at the surgical site, and lower overall medical costs. Accordingly, minimally invasive surgical techniques are being applied to an increasingly wider array of medical procedures.
FIG. 1 depicts a typical example of an endoscopic instrument 100. The instrument 100 may include a handle 110, a knob 120, and a tubular member 130. The handle 110 may be one of a variety of conventional configurations, such as a grip handle shown in FIG. 1. A portion of the handle 110 fits within the proximal end of the knob 120, providing an axis about which the knob 120 can be rotated. The distal end of the knob 120 may engage the proximal end of the tubular member 130, such that any rotation of the knob 120 may cause the tubular member 130 to rotate as well. The distal end of the distal member 130 may be adapted to include one of a variety of instruments or end effectors. For example, the distal end may be equipped with jaws, cutting blades, or some other instrument, depending on the desired use of the endoscopic instrument. It should therefore be appreciated that the term xe2x80x9cjawxe2x80x9d is used generically in this disclosure and should be interpreted to include other types of end effectors.
FIG. 2 is a partially sectioned view of an endoscopic instrument 100. As can be appreciated, the tubular member 130 may have a lumen 135 extending from the proximal end to the distal end. A drive rod 140 may be positioned within the lumen 135. At the proximal end of the endoscopic instrument, the drive rod 140 may be attached to the handle 110. The manner in which the drive rod 140 is attached to the handle 110 depends on the handle configuration, and is well known in the art. For example, in FIG. 2, the proximal end of the drive rod 140 is formed into a ball 142 and a portion of the handle 110 has a corresponding socket 112. As is conventionally known, actuating the handle 110 moves the drive rod 140 axially within the lumen 135. This axial movement of the drive rod 140 actuates the instrument at the distal end of the tubular member 130.
FIG. 3 is a partially sectioned view of the distal end of the tubular member 130 equipped with a jaw assembly 200. The jaw assembly 200 includes two jaw members 205, which partially overlap. Each jaw member 205 has a pivot hole 210 and a substantially oval drive groove 215. Each drive groove 215 may be arranged at an angle, such that when the two jaw members 205 are aligned and fully open, the drive grooves 215 form a xe2x80x9cVxe2x80x9d shape. A drive pin 220 may be inserted through the drive rod 140 and rides within the drive grooves 215.
FIG. 4 is an exploded view of the distal end of the tubular member 130 and jaw assembly 200, wherein like elements bear like reference numerals. A clevis 225 is formed in the distal end of the drive rod 140. The clevis 225 may be a xe2x80x9cUxe2x80x9d-shaped section and at least one of the arms 227 of the xe2x80x9cUxe2x80x9d may have a hole 230 to accommodate a drive pin 220. The distance between the arms 227 of the clevis 225 may be slightly larger than the width of the overlapping portions of the jaw members 205. When assembled, the overlapping portions of the jaw members 205 may be placed within the clevis 225. The drive pin 220 may be inserted through the at least one hole 230 in the arm 227 of the clevis 225 and through each of the drive grooves 215. A pivot pin 235 is then inserted into a hole 240 in the distal end of the tubular member 130 and through the pivot hole 210 in each of the jaw members 205.
The jaw assembly 200 may be operated as follows. When the jaws are open, the drive pin 220 is located near one end of the drive grooves 215, for example, the end closest to the pivot pin 235. As the handle 110 is actuated, the drive rod 140 moves axially. As the drive rod 140 moves axially, the drive pin 220, which is coupled to the drive rod 140, moves axially as well. As can be appreciated, the drive pin 220 moves through the drive grooves 215 of the jaw members 205. The pivot pin 235 prevents the jaw members 205 from moving axially into the tubular member 130. Rather, as the drive pin 220 moves through the drive grooves 215, the distal ends of the jaw members 205 move toward each other and the jaw closes. As is known in the art, the axial movement may result from either a xe2x80x9cpushxe2x80x9d or a xe2x80x9cpullxe2x80x9d action.
As can be appreciated, the amount of force required to close the jaws depends to a large extent on the characteristics of the material between the jaws. For example, thicker material may be more difficult to cut or compress than thinner material. As more force is exerted on the material, it is not uncommon for a portion of the clevis to fail under the stress. Typically, the point of failure occurs near where the drive pin is inserted in the clevis.
Accordingly, there is a need to provide an improved jaw assembly and drive rod configuration.
In accordance with the present invention, there is an endoscopic instrument having a tubular member, a handle, and a drive rod. The tubular member has a proximal end, a distal end, and a lumen extending therethrough. The handle is coupled to the proximal end of the tubular member and has an actuating mechanism. The drive rod is disposed within the lumen of the tubular member and has a proximal end and a distal end. The proximal end of the drive rod is coupled to the actuating mechanism of the handle such that the drive rod moves axially within the lumen in response to a change in force applied to the actuating mechanism. At least one boss protrudes radially from a portion of the drive rod near the distal end of the drive rod. In addition, at least one instrument member is pivotally connected to a pivot pin. The pivot pin is coupled to the distal end of the tubular member thereby preventing axial movement of the instrument member. A portion of the at least one instrument member is adapted to slidingly engage the at least one boss.
In accordance with another aspect of the invention, the at least one instrument member is a jaw member.
In accordance with yet another aspect of the invention, there is an endoscopic instrument having a tubular member, a handle coupled to the proximal end of the tubular member, and a drive rod disposed within the lumen of the tubular member. The handle includes an actuating mechanism, and the proximal end of the drive rod is coupled to the actuating mechanism of the handle such that the drive rod moves axially within the lumen in response to a change in force applied to the actuating mechanism. At least one boss protrudes radially from a portion of the drive rod near the distal end of the drive rod. At least one jaw member is pivotally connected to a pivot pin, the pivot pin being coupled to the distal end of the tubular member thereby preventing axial movement of the jaw member. A portion of the at least one jaw member has a groove, wherein the groove slid ingly engages the at least one boss.
In accordance with other aspects of the invention, a first jaw member is pivotally connected to the pivot pin and a second jaw member is fixedly connected to the distal end of the tubular member.
In accordance with yet another aspect of the invention, a first jaw member and a second jaw member are each pivotally connected to the pivot pin. A portion of each of the first jaw member and the second jaw member have a groove, wherein each groove slidingly engages a corresponding boss.
In accordance with still another aspect of the invention, each groove is open at one end.
In accordance with another aspect of the invention, each jaw member includes a stop. The stop of the first jaw member cooperates with the stop of the second jaw member to limit a range of pivotal rotation of the first jaw member and the second jaw member.
It should be emphasized that the term xe2x80x9ccomprisesxe2x80x9d or xe2x80x9ccomprising,xe2x80x9d when used in this specification, is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.